holler



(No Model.) 2 SheetsSheet 1.

P. G. 'MOLLER.

MAGHINB FOR GRINDING LITHOGRAPHIG STONES.

No. 268,119. Patented Nov. 28, 1882.

ATTORNEY N. PETERS. Plwlo-Ulhngraphcr. Washiugmn n. c.

(No Model.) 2 Sheets-Sheet 2.

1 Pyo. MULLER.

MACHINE FOR GRINDING LITHOGRAPHIG STONES. No. 268,119. Patented Nov. 28,188-2;

"Mg in ATTORNEY UNITED STATES PATENT OFFICE.

,PETER O. MULLER, F LEIPSIG, SAXONY, GERMANY, ASSIGNOR TO C. G. RGDER,OF SAME PLACE.

MACHINE FO-R GRINDING LITHOGRAPHIC STONES.

SPECIFICATION forming part of Letters Patent No. 268,119, dated November28, 1882.

Application filed June 10, 1882.

To all whom it may concern:

Be itknown that I, PETER OoRm'rz MoLLER, of Leipsic, Saxony, in theEmpire of Germany, have invented certain new and useful Improvements inMachines for Grinding Lithographic Stones, ofwhich the following is aspecification.

The machines used. for grinding off the surfaces of lithographic stoneswere objectionable for the reason that the grinding-plates soon losetheir plane surface and assume a convex or concave surface, so that itwas impossible to grind off the stones in a perfectly flat and uniformmanner. The convex or concave shape of the grinding-plates arose fromthe fact that they were compelled to move by the actuating mechanismcontinually in one and the same path over the stone, following exactlythe same lines of motion without any variation therefrom.

The object of this invention is to obviate the objection mentioned andfurnish an improved grinding-machine for lithographic stones, in which,by the use of a peculiarly-constructed actuating mechanism, thegrinding-plate receives an epicycloidal motion, and changes its pathwith each full revolution of the actuating mechanism, so that inconsequence thereof no irregularities on the surface of thegrindingplate can take place. Besides the improved motion of thegrinding-plate, the machine is furthermore provided with means for automatically supplying certain regulated quantities of sand and water tothe face of the stone, so that the machine requires little supervision,while much better results are obtained than by the old method, in whichthe sand is supplied by hand in irregular quantities and at irregularintervals of time, so as to get in between the movable parts of themachine and exert an injurious influence upon the same.

The invention consists therefore, first, of an improved mechanism inconnection with an epicycloidal wheel, whereby the axially-turninggrinding-plate receives an epicycloidal motion which changes its pathwith each revolution of the driving-shaft; secondly, ofautomatically-operatin g devices for supplying sand and water to thestone at regular intervals of time, and in uniform quantities tothatpart (No model.)

of the lithographic stone which is not covered by the grinding-plate.

In the accompanying drawings, which fully illustrate my invention,Figures 1, 2, and 3 represent respectively a side elevation, an endelevation, and a plan, of my improved machine for grinding lithographicstones. Fig. 4 is a diagram showing the epicycloidal motion of thegrinding-plate and the change in the path of the same for eachrevolution of the drivingshaft; and Figs. 5, 6, and 7. are respectivelya detail side view, a vertical central section, and a plan, of themechanism for imparting motion to the grinding-plate, and of the sandand water supplying devices.

Similar letters of reference indicate corresponding parts.

The entire grinding mechanism is supported on a frame, a a, which isbraced at the middle of its height and adapted to support a foundationor bed-plate, v, for the reception of the lithographic stone G, thesurface of which has to be ground, and whose accurate adjustment isobtained by set'screws e e and blocks. The supporting-frame a a carriesat its upper end a circular top plate, t', which is toothed at its innercircumference, so that it forms at the same time the main gear-wheel ofthe actuating mechanism of the grinding-plate. To the circular topplate, 71, is rigidly secured the top bearing-frame, m, which carriesthe different motion-transmitting parts of the machine.

The actuating mechanism of the grindingplate h is set in motion by ahorizontal shaft, cl, which carries a flywheel and driving-pulley, andwhich is supported in bearings of the frame m. From the driving-shaft 01motion is transmitted by bevel-gears c c to the vertical shaft d, andthe crank disk f, keyed to the lower end of the same. The crank-disk fis provided with an eccentric crank-pin, f, to which a pinion, k, is soapplied that it turns loosely on ajournal of the pin. The pinion 7tmeshes with the interior gear of the circular top plate, '5, and travelsalong the inner circumference of the same. To the pinion L iseccentrically secured a spindle, 20, which carries at its lower end thegrinding-plate 71, so that the latter can turn loosely thereon aroundits axis.

2 Y 2cs,1 19

The described transmitting mechanisms impart a compound motion to thegrinding-plate h, as shown in Fig. 4-viz., a simple circular motion bythe crank-disk f, and a second rolling or cycloidal motion by means ofthe interior gear-wheel of the plate 2 and the eccentric position of therod to on the pinion k. The number of teeth of the pinion 7c and of theinterior gear-wheel of the top plate, 1', are intentionally so selectedrelatively to each other that the path on line of motion of thegrinding-plate moves forward for each full revolution of the crank-diskf the distance of the width of one or more teeth, whereby the differentpaths or lines of motion of the grindingplate will never coincide witheach other. The grinding-plate is consequently compelled to attackcontinually different points of the lithographic stone, so that anyirregular grinding off of the stone or an irregular shape of thegrinding-plate is fully prevented. Besides the compound motion which isimparted to the grinding-plate by the transmitting mechanisms described,the same may also turn freely around its own axis, so that consequentlythe object of moving the grinding-plate in continually varying and neveroverlapping curves over the stone is fully achieved.

The angles of the triangles (shown in dotted lines in Fig. 4) show thesuccessive positions reached by the spindle '10 at each revolution ofthe pinion K, as said pinion advances. Since the spindle w is attachedto the grinding-plate these angles mark the successive positions of thecenter of the grinding-plate-in its revolution about the crank-disk f.

The automatically-operating devices for supplying sand and water to thestone are shown in Figs. 5, 6, and 7, and are applied to the crank-diskf. The latter is for this purpose provided with two deep concentricgrooves or troughs, r r and r r, of which the exterior oneisintended forreceiving sand, the interior for the reception of water. The water isconducted to the groove 1" by a tube provided with a stop cook, the tubedischarging the required quantity through afunnel, t, (shown in Figs. 1and 5,) to the groove 0', from which it passes through a small tube, 19,to the stone. The sand is supplied from a vessel or reservoir, 8,supported at the top of the frame or through a vertical connecting-tube,s, into a funnel, t, and thence into the groove 1*, which is provided atone point thereof with a. small discharge-perforation, u.

To the horizontal plate of the frame m, immediately abovethe crank-diskf, are secured two vertically-adjustable clearing-pins, z 2,

which extend downward and nearly to the bottom of the groove 1", so thatat each revolution of the crank-disk a certain determined quantity ofsand is supplied twice through the hole u to the stone. The sand dropsafter leaving the hole 20 on adeflecting-plate, q, which may be set toany suitable angle of inclination, according to the point to which thesand is to be deposited on the stone. The disch arge-openings of thewater and sand are so arranged-relatively to the grinding-plate thatthey are not discharged upon the same, but always directly upon thestone. The result is a uniform and automatical supply of water and sandto the stone, so that the grinding operation proceeds throughout in aregular and highly satisfactory manner.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. In a machine for grinding lithographic stones, afixed bed-plate for supporting the stone, adjusting set-screws andblocks, a main shaft, and a verticalsh aftcarryin g bevel-gears, acrank-disk, an eccentric crank-pin, a pinion turning loosely on ajournalof the pin, a circular top plate geared on its inner circumferencemeshing with the pinion, a spindle secured to the pinion, thegrinding-plate turning loosely on the spindle, and devices by which sandand water are automatically'supplied to the stone, substantially asdescribed.

2. In a machine for grinding lithographic stones, the combination of thedriving-shaft d, bevel-gears c 0, vertical shaft 01, crank-disk f,having pinf, eccentrically-connected pinion k, circular top plate, '5,having a gear-wheel at its inner circumference, and grinding-plate h,turning loosely on the eccentric spindle w of pinion 7c, substantiallyas set forth.

3. In a machine for grinding lithographic stones, the combination of asand-vessel, 8, connecting-tube s, funnel t, crank-diskf, having acircular trough, 1', adjustable clearing-pins 2, extending into thegroove r, discharge-hole u, and deflecting-plate q, substantially as setforth.

4:. In a machine for grinding lithographic stones, theconibination ofawater-supply pipe, funnel t, crank-disk], havingacircular trough, r,and a small discharge-pipe, 11, substantially as specified.

In testimony that I claim the foregoing as my invention 1- have signedmy name in presence of two subscribing witnesses.

PETER GORFITZ MOLLER.

Witnesses:

J OHANNES BEoK, FRED. WILKIE.

